I think than this is possible, because between the smooth muscle cells there are gap junctions, but where i can look for more information? thanks in advance
P.D: this is a new issue for me
I am unable to answer this question specifically in relation to urethral smooth muscle (someone else no doubt will in time), but as you are a non-biological engineer I thought I'd provide you with a brief background of the basis of the question you are asking. In blood vessels, particularly the microcirculation, endothelial cells are connected by large and numerous gap junction plaques, which permit the passage of current and small molecule chemical messengers. In many small vessels (but generally not large vessels) endothelial cells are also connected to the subintimal layer of smooth muscle cells via gap junctions. Smooth muscle cells can also connect to each other in this way. Physiologically, focal endothelial stimulation by agonists or a local increase in shear stress can hyperpolarize the endothelium, which spreads to the smooth muscle via myoendothelial gap junctions, dilating that segment of artery. To coordinate vessel behaviour, this hyperpolarization also spreads rapidly between endothelial cells (which, having gap junction plaques much larger than those connecting endothelial and smooth muscle and between neighbouring smooth muscle cells, are much lower resistant) over biologically large distances to downstream vessels and upstream feed arteries. This functions to increase blood flow to a local microvascular network from a focal point of stimulation, and is generally termed "conducted vasodilation".
Whether an analogous mechanism occurs in the urethra I simply don't know. But I thought it might be helpful to provide you with an example of the physiological basis of your question.
Hi David, thanks for your answer and for your time, i was reading about the electrical activity in the rabbit urethra, and there are a specialized type of cell (interstitial cells) than can be related with the current, and iwith the contraction of the urethra. But, i dont know if this happens same in the human body.
Hi, Don Julio Cesar: How is the CYCY doing these days? Well, your question sounds like a very painful situation. But seriously. Because you recognize that this is a new field for you, I think your question may be more appropriately answered in general terms. First, gap junctions made of connexins (in vertebrates) can be found practically in every tissue and cell type you look for them, even if the protein expression be low and big plaques are not easily located; some exceptions include sperm and adult skeletal muscle. Second, wherever they are found, gap junctions would facilitate the homogenization of the resting potential of neighboring cells (that is, electrical charges will travel across boundaries by virtue of the voltage gradient, thus decreasing such voltage gradient); in addition, other small molecules can also travel across gap junctions. Third, all cells are electrical entities, since they have a trans-membrane potential as well as membrane proteins that separate charges to maintain such potential. Fourth, interstitial (or Cajal-like) cells have been suggested to be the pacemakers elements in tissues with spontaneous, slow contractions (like the intestine and urethra) in animal models. Fifth, and more important for your perception: we use animal models because they often represent well what happens in the human body. In other words, there is a good chance that phenomena observed in animal tissues/cells also occur in humans, at least at a non-integrative level.
David has offered you a good answer that shall stimulate your further reading of the literature. I also strongly encourage you to do so. The field of gap junctions is very very interesting, and after almost 50 years of work and finding diseases related to connexin mutations, we have just started: there is still much to learn.
Hi José, thanks for your answer. I have already read more about the gap junction, and yes, is a very interesting field. So, i think than enhance this gap junction between the cells ( i talk in the tissue engineering field) with a conductive scaffold, it is probable than exist more cell proliferation. What do you think? Thanks in advance.
Julio
Hi, Don Julio: I do not quite understand your question. Are you asking whether the presence of gap junctions would increase cell proliferation? Yes, it is possible, and it is possible as well that gap junctions would decrease proliferation. Such variability depends on the type of cells (perhaps because each cell type has its own regulatory pathways) and gap junction proteins thereby expressed (because each connexin channel has its own permeability and selectivity characteristics, and that determines which message can or cannot go from cell to cell). Such regulation may depend on electrical or molecular signals. Gap junctions are in essence simple means of transmitting the existing or emergent messages, but they do have their preferences. There is a wealth of information. Regarding your question, I suggest you take a look at the following, just to spike your curiosity:
Connexin 37 profoundly slows cell cycle progression in rat insulinoma cells. Burt JM, Nelson TK, Simon AM, Fang JS. Am J Physiol Cell Physiol. 2008 Nov;295(5):C1103-12. doi: 10.1152/ajpcell.299.2008. Epub 2008 Aug 27.
Gap junctions are involved in the early generation of left-right asymmetry. Levin M, Mercola M. Dev Biol. 1998 Nov 1;203(1):90-105.
Hello José Francisto, I had not seen your message, thank you very much for your answe.
Hi Julio Cesar, Just i would like to know the benefit of this study ?
- Badges
- Science topic
- Similar topics
- Medicine
- Disease
- Infectious Diseases